PEEP IDENTIFICATION

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1 • This Semipalmated Sandpiper (center left ) is the darkest bird and stands out amid a group of Western Sandpipers. Juvenile Western Sandpipers begin molting almost as soon as they leave the arctic. By October, most Westerns are an even gray color. Juve - 3 nile Semipalmated Sandpipers molt little if at all before leaving North America, and a straggler can easily be picked out in October by its dark brown color. Note also the differences in structure. The Semipalmated has a small head, almost no neck, and a full, rounded belly. The Westerns have larger heads, leaner bodies, and longer legs. Avalon, New Jersey; September 2005. © Tony Leukering.

2 • On the Atlantic Coast, female Semipalmated Sandpipers with relatively long bills are regularly seen. This individual has a long and tapered bill, but it is not an extreme example. Some female Semipalmated Sandpipers can have even longer bills that droop no - ticeably. That is why bill shape is better considered a supporting mark, rather than a definitive characteristic, for separating Western and Semipalmated Sandpipers. This is certainly a Semipalmated because it retains full juvenal plumage in October, and has a small head and fat body. Avalon, New Jersey; October 2005. © Cameron Cox.

3 • This is a straightforward identification: Western Sandpiper (left) and Semipalmated Sandpiper (right), both in alternate plumage. The difference in body shape is well-displayed here: Western is lanky; Semipalmated is round. Situations like this provide the perfect opportunity for becoming familiar with differences in structure, which can be used when plumage characters are less obvious. Weld County, Colorado; April 2006. © Bill Schmoker.

40w1 BIRDING • JULY/AUGUST 2008 PEEP IDENTIFICATION

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1 • All peeps can be territorial at times, but Semipalmated Sand - pipers are particularly aggressive. On the Pacific coast, where Western Sandpiper is by far the most common “standard peep,” Semipalmated Sand - pipers can sometimes be picked out from the masses of Westerns by the aggressive behavior that is displayed even by juveniles. Jamaica Bay Wildlife Refuge, New York; August 2005. © Kevin T. Karlson.

2 • Large, long-billed female Western Sandpipers sometimes give the im - pression of being miniature Dunlin. Comparing these two adult Western Sandpipers (left) with the first-cycle Dunlin (right), some basic similarities are evident. Dunlin are always larger, with heavier bodies and proportion - 2 ally smaller heads than Western Sandpipers. They are also longer-billed, although this distinction is sometimes difficult to judge. If in doubt, recall that Dunlin have much larger eyes and heavier legs than any peep. High Island, Texas; April 2005. © Kevin T. Karlson.

40w2 BIRDING • JULY/AUGUST 2008 PEEP IDENTIFICATION

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1 • Most of the birds in this feeding flock are Least Sandpipers . Notice how the breasts of the probing indi - viduals almost scrape the ground. In the midst of this group is a White- rumped Sandpiper (third from left ). It stands out from the Least Sand - pipers because of its larger size, longer body, and paler gray color overall. The attenuated body shape and long primary projection of the White-rumped are evident even in this distant photo. Cape May, New Jer - sey; August 2004. © Richard Crossley.

2 • Notice how the primaries and tail of this White-rumped Sandpiper are tipped above the back. The “long-winged peeps,” particularly White-rumped, have a feeding mo - tion that calls to mind a seesaw. As the head goes down to the surface, the tail rises above the back, the head comes up again, the tail goes down again, etc. Smaller peeps show minimal tipping as they feed; 2 their tails rarely rise above the back. The exception is in aggressive displays, when any peep 3 may feed with its wings drooped and its tail pointed al - most straight up. In this situation, though, the tail stays pointed up independent of what the bird does with its head; thus, it still does not give a seesaw impression. Jamaica Bay Wildlife Refuge, New York; August 2005. © Kevin T. Karlson.

3 • Peeps often do not pose nicely for identification. But many uncooperative birds can be correctly named based on observations of structure and behavior, and visible plumage traits. Here, the distinctly crossed pri - maries and tipped-forward posture eliminate all possi - bilities except White-rumped and Baird’s Sandpipers. The bird’s distinct forward bend strongly favors White- rumped. This conclusion is further supported by what can be seen of the head, which looks relatively large. The behavior also fits White-rumped: Baird’s rarely feeds by probing. In this photo, the clincher for White- rumped Sandpiper is the streaking along the flanks, eliminating Baird’s. Anahuac National Wildlife Refuge, Texas; April 2006. © Cameron Cox.

40w3 BIRDING • JULY/AUGUST 2008 PEEP IDENTIFICATION

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1 • This photo of three Least Sand - pipers and a Baird’s Sandpiper (right ) is interesting for a number of reasons. It plainly illustrates how Least Sandpipers can sometimes adopt a feeding stance that is similar to that of other peeps. It is rare for Least to feed in this manner, but it does happen. The photo also shows how leg color can be misjudged; here, the legs of all individuals are caked in mud. The short legs of the Baird’s Sandpiper are evident, as are its small head and long body. The overall look of the head of the Baird’s and the rightmost Least is surprising - ly similar. Cape May, New Jersey; Sep - tember 2003. © Richard Crossley.

2 • Here, the whole suite of Baird’s Sandpiper ’s distinctive structural traits is displayed. The long, crossed primaries immediately put this bird 2 in the “long-winged peep” category. The broad shoulders, the flat back, the small head, 3 and the slender bill all point to Baird’s and eliminate White-rumped Sandpiper. Additionally, Baird’s and Least Sandpipers love to feed on floating mats of al - gae, while other peeps seem to shun them. Port Su - san, Washington; August 2006. © Cameron Cox.

3 • This head-on Baird’s Sandpiper shows a body profile typical of the species. The oval-shaped body of Baird’s is unique among the peeps. Compared to other peeps, Baird’s appears to have broader shoul - ders but a shallower chest. From above, the species seems to have a very wide, flat backs. This oval shape is not depicted in North American field guides, but is well-illustrated in Birds of Europe by Killian Mullarney and colleagues. Isles of Scilly, Unit - ed Kingdom; September 2006. © Neil Loverock.

40w4 BIRDING • JULY/AUGUST 2008